Apparatus for connecting two turbine housings of a two-stage turbocharger system

ABSTRACT

An apparatus for connecting an exhaust gas outlet of a first turbine housing with an exhaust gas inlet of a second turbine housing of a two-stage turbocharger system, which features a pocket that is situated in the area of a first flange on the first turbine housing and features a projection that is arranged in the area of a second flange on the second turbine housing and is able to be inserted into the pocket. The projection is designed such that, after the projection has been inserted into the pocket, the first and second turbine housings are able to be tilted in relation to each other in order to establish a flush connection between the first flange and the second flange.

THE FIELD OF THE INVENTION

The present invention relates to an apparatus for connecting two turbinehousings, a two-stage turbocharger system, and a method for assembling atwo-stage turbocharger system.

BACKGROUND OF THE INVENTION

The basic development goals for future combustion engines makeincreasingly refined charging systems necessary. The design of such aturbocharger system leads to conflicting goals in terms of the powerrating of the engine on the one hand and the transient response and thetorque power band on the other hand. A high power rating necessitates arelatively large exhaust gas turbocharger. The desire for very highboost pressure even at low engine speeds means, however, that theturbocharger needs to be made much smaller. A combination of the twowould be ideal.

Regulated two-stage turbocharging systems are being developed in orderto resolve this conflict. Systems of this kind allow for thecontinuously variable adaptation of the turbine and compressor sides ofthe system for each engine operating point. The regulated two-stageturbocharger system consists of two turbochargers of different sizesconnected in series that utilize bypass regulation. The exhaust gas massflow coming from the cylinders first reaches the exhaust manifold. Here,it is possible to expand the entire exhaust mass flow using the highpressure turbine (HP) or to redirect some of the mass flow through abypass to the low pressure turbine (LP). The entire exhaust mass flow isthen utilized again by the low pressure turbine (LP). The entire freshair flow is initially compressed by the low pressure stage. Furthercompression subsequently occurs in the high-pressure stage. Regulatedtwo-stage turbocharging therefore allows for continuous adaptation onthe turbine and compressor sides to the requirements of the operatingengine.

As a result of the lack of space in the area surrounding an internalcombustion engine, turbocharging systems of this sort must be designedto be as small as possible. In order to accomplish this, the two turbinehousings are to be joined directly together. Since both the two turbinehousings as well as the two compressor housings must be fluidicallyconnected with each other, this can lead to problems during assembly. Inaddition, it is difficult to position the two housings correctly inrelation to one another and to join them together in a fluid-tightmanner.

The object of the present invention is therefore to provide an apparatusfor connecting two turbine housings which permits simple assembly and,at the same time, precise positioning and fluid-tight joining of theturbine housings.

SUMMARY OF THE INVENTION

The present invention relates to an apparatus for connecting an exhaustgas outlet of a first turbine housing with an exhaust gas inlet of asecond turbine housing according to claim 1, a two-stage turbochargersystem according to claim 6, and a method for assembling a two-stageturbocharger system according to claim 14.

The apparatus according to the invention for connecting an exhaust gasoutlet of a first turbine housing with an exhaust gas inlet of a secondturbine housing of a two-stage turbocharger system features a pocket,which is situated in the area of a first flange on the first turbinehousing, and a projection, which is situated in the area of a secondflange on the second turbine housing and is able to be inserted into thepocket. The projection is designed such that, after the projection hasbeen inserted into the pocket, the first and second turbine housings canbe tilted in relation to each other in order to establish a flushconnection between the first flange and the second flange. One advantageof this apparatus is that the two turbocharger assemblies can beassembled and calibrated separately from one another. As a result of thetilting movement, significant pressure can in a simple manner be exertedagainst a seal between the two turbine housings. The risk of leakage isconsequently reduced. In embodiments, this apparatus allows foraccomplishing the connection between the turbine housings as well as theconnection between the two compressor housings by way of a single motionduring assembly.

In embodiments, the pocket can be situated in a wall of the firstturbine housing extending from the first flange.

In embodiments able to be combined with all of the embodiments describedthus far, the projection may be designed in the form of a stripextending in a linear direction from an outer wall of the second turbinehousing and running approximately parallel to a plane along which lies aconnection area for the second flange.

In embodiments able to be combined with all of the embodiments describedthus far, the projection can have a lower side, which is disposedopposite a connection area on the first flange and features a chamfer.The chamfer may have a chamfer angle of from 2° to 7°, in particularfrom 4° to 5°.

In embodiments able to be combined with all of the embodiments describedthus far, at least one connection means may be provided in order toattach the second turbine housing to the first turbine housing.

In embodiments able to be combined with all of the embodiments describedthus far, a seal can be situated between the first flange and the secondflange. Through the tilting motion, both connection areas of the firstand second flanges are pressed together with significant force. In theprocess, the seal is compressed between the two connection areas. Therisk of leakage is consequently decreased.

Furthermore, in embodiments able to be combined with all of theembodiments described thus far, at least one locating pin may beprovided in order to establish the position of the second turbinehousing in relation to the first turbine housing during assembly. Thelocating pin may be situated in the connection area of the first flangeand interact with the projection in order to position the first andsecond turbine housings in relation to one another.

The invention furthermore comprises a two-stage turbocharger systemhaving a first exhaust gas turbocharger with a first turbine housing andhaving a second exhaust gas turbocharger with a second turbine housing.Situated in the area of a first flange on the first turbine housing, thefirst turbine housing features a pocket, into which projects aprojection, which is situated in the area of a second flange on thesecond turbine housing. Regarding the connection between the first andthe second turbine housings, the projection is designed such that, afterthe projection has been inserted into the pocket, the first and secondturbine housings can be tilted in relation to each other in order toestablish a flush connection between the first flange and the secondflange.

In embodiments of the two-stage turbocharger system, the pocket can besituated in a wall of the first turbine housing extending from the firstflange.

In embodiments of the two-stage turbocharger system able to be combinedwith all of the embodiments described thus far, the projection may bedesigned in the form of a strip extending in a linear direction from anouter wall of the second turbine housing and running approximatelyparallel to a plane along which lies a connection area for the secondflange.

In embodiments of the two-stage turbocharger system able to be combinedwith all of the embodiments described thus far, the projection can havea lower side, which is disposed opposite a connection area on the firstflange and features a chamfer. The chamfer may have a chamfer angle offrom 2° to 7°, in particular from 4° to 5°.

In embodiments of the two-stage turbocharger system able to be combinedwith all of the embodiments described thus far, at least one connectionmeans may be provided in order to attach the second turbine housing tothe first turbine housing.

In embodiments of the two-stage turbocharger system able to be combinedwith all of the embodiments described thus far, a seal can be situatedbetween the first flange and the second flange.

Furthermore, in embodiments of the two-stage turbocharger system able tobe combined with all of the embodiments described thus far, at least onelocating pin may be provided in order to establish the position of thesecond turbine housing in relation to the first turbine housing duringassembly. The locating pin can be situated in the connection area of thefirst flange and interact with the projection in order to position thefirst and second turbine housings in relation to one another.

In embodiments of the two-stage turbocharger system able to be combinedwith all of the embodiments described thus far, the two-stageturbocharger system may furthermore feature a first compressor housinghaving a compressor inlet and a second compressor housing having acompressor outlet, whereby the compressor inlet and the compressoroutlet are connectable with one another by way of a plug connection. Theplug connection can be designed to have a tubular shape and feature arigid center tube as well as a flexible outer casing. There can be asealing bead at each end of the tube-shaped plug connector. The elasticouter casing has the advantage of being able to compensate fortolerances. On the other hand, it aids in sealing the connection betweenthe two compressor housings. Due to how the plug connection isconstructed (rigid center tube and flexible outer casing), rotating itat an angle of 10° can serve to connect the (compressor) housings withone another. This increases the flexibility of the design with regard tohow the two turbocharger assemblies are positioned with respect to oneanother. The plug connection furthermore allows the two turbochargerassemblies to be connected in a single assembly step, during which asuitably tight fluidic connection is simultaneously made between bothturbine housings and both compressor housings.

The invention furthermore comprises a method for assembling a two-stageturbocharger system having a first exhaust gas turbocharger with a firstturbine housing, and having a second exhaust gas turbocharger with asecond turbine housing, whereby the method comprises the followingsteps: inserting a projection on the second turbine housing into apocket on the first turbine housing; tilting the first turbine housingand the second turbine housing in relation to one another such that afirst flange on the first turbine housing is situated flush against asecond flange on the second turbine housing; and attaching the firstturbine housing to the second turbine housing.

In embodiments, the method may furthermore comprise: connecting acompressor inlet of a first compressor of the two-stage turbochargersystem with a compressor outlet of a second compressor of the two-stageturbocharger system by way of a plug connection during the insertion ofthe projection into the pocket.

Additional details and features of the invention are described inreference to the drawings as follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a first detail of a section of a first embodiment of theinventive two-stage turbocharger system;

FIG. 2 shows a second detail of a section of the inventive two-stageturbocharger system according to the first embodiment;

FIG. 3 shows three section views of the inventive apparatus forconnecting two turbine housings in accordance with an embodiment.

DETAILED DESCRIPTION

Embodiments of the inventive apparatus for connecting two turbinehousings of a corresponding two-stage turbocharger system will bedescribed in reference to the drawings as follows. All of the followingdetails and advantages apply to the connecting apparatus as well as tothe two-stage turbocharger system having a corresponding apparatus. Amethod for assembling a two-stage turbocharger system will also bedescribed.

FIG. 1 and FIG. 2 each show a detail of a section of a two-stageturbocharger system 10. The two-stage turbocharger system 10 comprises afirst exhaust gas turbocharger 100 and a second exhaust gas turbocharger200, each having a turbine and a compressor. The turbocharger system 10has a first turbine housing 110 and a second turbine housing 210 as wellas a first compressor housing 300 and a second compressor housing 400.The two turbine housings 110, 210 shown in the FIG. 1 view are not yetconnected with one another. In the FIG. 2 view, the two turbine housings110, 220 are shown connected via the inventive apparatus for connectingthe exhaust gas outlet 112 of the first turbine housing 110 with theexhaust gas inlet 212 of the second turbine housing 210 in the two-stageturbocharger system 10. In FIG. 3 are three expanded section views ofthe connecting apparatus, whereby the process for connecting togetherthe first and second turbine housings 110, 210 is shown in chronologicalsequence.

The connecting apparatus features a pocket 130 situated in the area ofthe first flange 120 of the first turbine housing 110 as well as aprojection 230, which is situated in the area of the second flange 220of the second turbine housing 210. The projection 230 is inserted intothe pocket 130 in order to connect the two turbine housings 110, 210.The projection 230 is designed such that, after the projection 230 hasbeen inserted into the pocket 130, the first and second turbine housings110, 210 can be tilted in relation to each other in order to establish aflush connection between the first flange 120 and the second flange 220.This is made evident by comparing FIG. 1 with FIG. 2: a gap exists atthe bottom right of FIG. 1 between the first flange 120 of the firstturbine housing 110 and the second flange 220 of the second turbinehousing 210. In FIG. 2, the first flange 120 and the second flange 220are flush against one another and are providing a fluid-tight connectionbetween the first and second turbine housings 110, 210. The movement ofthe two connecting apparatus components—the pocket 130 and theprojection 230—in relation to one another during the connection process,for example during the final assembly of the two-stage turbochargersystem 10, is shown in FIG. 3. It is also clearly evident from FIG. 3how the projection 230 is tilted subsequent to being inserted into thepocket 130 (middle and lower illustration). One advantage of thisapparatus is that the two turbocharger assemblies can be assembled andcalibrated separately from one another prior to being joined together.As a result of the tilting movement of the two turbine housings 110, 210in relation to one another during the connecting process, significantpressure can in a simple manner be exerted against the seal 600 that issituated between the two turbine housings 110, 210, or, morespecifically, between the first flange 120 and the second flange 220.The significant pressure against the seal 600 can, for example, lead toa compression of the seal leading to a reduction of its thicknessmeasuring from 0.1 to 0.3 mm. As a result, the risk of leakage isreduced in this transitional area between the two turbine housings 110,210. In embodiments, the connecting apparatus allows for accomplishingthe connection between the turbine housings 110, 210 as well as theconnection between the two compressor housings 300, 400 by way of asingle movement during assembly (more regarding this hereinafter).

As shown in FIG. 1 and in FIG. 2, the pocket 130 can be situated in awall of the first turbine housing 110 extending from the first flange120. The pocket 130 is formed as a groove running in a linear direction.In other words, the pocket 130 is a straight-line depression runningalong the border between the first flange 120 and the wall extendingfrom the first flange 120. The cross section of the pocket 130 can beapproximately rectangular or u-shaped. The projection 230 is designed inthe form of a strip extending in a linear direction from an outer wall214 of the second turbine housing 210 and running approximately parallelto a plane along which lies a connection area 222 for the second flange220 (see FIG. 1).

The projection 230 has a lower side 232, which is disposed opposite aconnection area 122 on the first flange 120 (see FIG. 1) and features achamfer 234. The chamfer 234 is in particular evident from theillustrations in FIG. 3. The chamfer 234 may, for example, have achamfer angle of from 2° to 7°, in particular from 4° to 5°. In otherwords, the projection 230 formed as a strip has a lower side 232, atleast some extent of which is not exactly parallel to the connectionarea 222 of the second flange 220, but at least some extent of which israther inclined slightly upward. The angle of inclination corresponds tothe aforementioned chamfer angle.

Once the first flange 120 and the second flange 220 are situated flushagainst one another, then at least one connection means 700 can be putin place in order to attach the second turbine housing 210 to the firstturbine housing 110 (see FIG. 2). In embodiments, for example twoconnection means 700 can be provided that are situated on theapproximately opposite sides of the exhaust gas inlet 212. Suitable foruse as connection means 700 are, for example, expansion pins, set screwswith nuts (as shown in FIG. 2), screws, clamps, brackets, or the like.

As was already referred to above, a seal 600 can be situated between thefirst flange 120 and the second flange 220. Through the tilting motion,both connection areas 122, 222 of the first and second flanges 120, 220are pressed together with significant force. In the process, the seal iscompressed between the two connection areas 122, 222. This readilyapparent from the illustration at the bottom of FIG. 3. As a result, therisk of exhaust gases leaking in this connection area is furtherreduced.

Furthermore, the apparatus for connecting the two turbine housings 110,210 can be provided with at least one locating pin 140 in order toestablish the position of the second turbine housing 210 in relation tothe first turbine housing 110 during assembly. The locating pin 140 can,for example, be situated in the connection area 122 of the first flange120 (as indicated in FIG. 1) and interact with the projection 230 (forexample a recess in the projection 230) in order to position the firstand second turbine housings 110 to 210 in relation to one another.

The joining of the compressor inlet 310 of the first compressor housing300 with the compressor outlet 410 of the second compressor housing 400will be described in reference to FIG. 1 and FIG. 2 as follows. Thecompressor inlet 310 is connected with the compressor outlet 410 using aso-called Plug&Seal connection unit. This comprises a tube-shaped plugconnector 500 that extends from the compressor inlet 310 into thecompressor outlet 410. The plug connector 500 features, for example, arigid center tube and an elastic outer casing. In addition, a sealingbead 510 is provided at each end of the plug connector 500. The centertube can, for example, be manufactured from metal (preferably stainlesssteel). The outer casing can, for example, be a rubber coating. Oneadvantage of the elastic outer casing is the ability to compensate fortolerances, because the rubber coating is flexible and can be compressedduring assembly. On the other hand, the rubber coating helps in sealingthe connection between the two compressor housings 300, 400. During theassembly procedure for the two-stage turbocharger system 10, theconnection tube 500 in the second compressor housing 400 can, forexample, be assembled in advance (see FIG. 1) as well as inserted at anappropriate angle into the first compressor housing 300. In doing so, agap will remain between the two housings (see FIG. 1 and FIG. 2), whichis also still present subsequent to the tilting movement of the twoturbine housings 110, 210 in relation to one another. In the exampleshown, this gap is approximately 4-5 mm wide. Depending on thearrangement and installed location of the two-stage turbocharger system10, the gap may be larger or smaller. The length of the connector plug500 as well as its construction (for example, greater elasticity inorder to compensate for the relevant positions of the two turbinehousings with respect to each other) can be adjusted accordingly. Due tohow the plug connection 500 is constructed (rigid center tube, flexibleouter casing, and a sealing bead 510 at both ends), a rotation or anangle of, for example, up to 10° can serve to connect the compressorhousings 300, 400 (or rather the inlet 310 and outlet 410 thereof) withone another. The rotation relates in this context to an angle betweenthe central longitudinal axis of the compressor outlet 410 and thecentral longitudinal axis of the compressor inlet 310. This increasesthe flexibility of the design with regard to how the two turbochargerassemblies are positioned in relation to one another. The plugconnection 500 furthermore allows the two turbocharger assemblies to beconnected in a single assembly step, during which a suitably tightfluidic connection is simultaneously made between both turbine housingsand both compressor housings.

The method for assembling a two-stage turbocharger system will also bebriefly discussed as follows. Initially, the two turbocharger assembliesmay be assembled completely independently of one another. The firstexhaust gas turbocharger 100 is then joined with the first turbinehousing 110, and the second exhaust gas turbocharger 200 is joined withthe second turbine housing 210, whereby the projection 230 of the secondturbine housing 210 is inserted into the pocket 130 of the first turbinehousing 110. This step is apparent in FIG. 1 and in the upper and middleillustrations in FIG. 3. The first turbine housing 110 is then tilted inrelation to the second turbine housing 210 such that the first flange120 of the first turbine housing 110 is situated flush against thesecond flange 220 of the second turbine housing 210 (see FIG. 2 and thelower illustration in FIG. 3). Finally, the first turbine housing 110can then be attached to the second turbine housing 210, for exampleusing the connection means 700.

While the projection 230 on the second turbine housing 210 is beinginserted into the pocket 130 of the first turbine housing 110, thecompressor inlet 310 of the first compressor is able to be connectedwith the compressor outlet 410 of the second compressor of the two-stageturbocharger system 10. This can take place, for example, by way of theplug connector 500. The plug connector 500 can, for example, have beenpreviously inserted into the compressor outlet 410 of the secondcompressor housing 400. As a consequence, the two compressor housings300, 400 as well as the two turbine housings 110, 210 can then be joinedtogether. This approach not only simplifies assembly, but also reducesassembly time considerably. In addition, it is thereby possible tocompletely assemble the two turbocharger assemblies separately from oneanother.

Although the present invention has been described above and is definedin the attached claims, it should be understood that the invention mayalternatively be defined in accordance with the following embodiments:

-   1. Apparatus for connecting an exhaust gas outlet (112) of a first    turbine housing (110) with an exhaust gas inlet (212) of a second    turbine housing (210) in a two-stage turbocharger system (10) having    -   a pocket (130) situated in the area of a first flange (120) on        the first turbine housing (110), and    -   a projection (230), which is situated in the area of a second        flange (220) on the second turbine housing (210) and can be        inserted into the pocket (130), characterized in that the        projection (230) is designed such that, after the projection        (230) has been inserted into the pocket (130), the first and        second turbine housings (110, 210) can be tilted in relation to        one another in order to establish a flush connection between the        first flange (120) and the second flange (220).-   2. Apparatus according to embodiment 1, characterized in that the    pocket (130) is situated in a wall of the first turbine housing    (110) extending from the first flange (120).-   3. Apparatus according to embodiment 1 or embodiment 2,    characterized in that the projection (230) is designed in the form    of a strip, which extends in a linear direction from an outer wall    (214) of the second turbine housing (210) and runs approximately    parallel to a plane along which lies a connection area (222) for the    second flange (220).-   4. Apparatus according to any of the preceding embodiments,    characterized in that the projection (230) has a lower side (232),    which is disposed opposite a connection area (122) on the first    flange (120) and features a chamfer (234).-   5. Apparatus according to embodiment 4, characterized in that the    chamfer (234) has a chamfer angle of from 2° to 7°, in particular    from 4° to 5°.-   6. Apparatus according to any of the preceding embodiments,    characterized in that at least one connection means (700) is    provided in order to attach the second turbine housing (210) to the    first turbine housing (110).-   7. Apparatus according to any of the preceding embodiments,    characterized in that a seal (600) is situated between the first    flange (120) and the second flange (220).-   8. Apparatus according to any of the preceding embodiments,    characterized in that furthermore at least one locating pin (140) is    provided in order to establish the position of the second turbine    housing (210) in relation to the first turbine housing (110) during    assembly.-   9. Apparatus according to embodiment 8, characterized in that the    locating pin (140) is situated in the connection area (122) of the    first flange (120) and interacts with the projection (230) in order    to position the first and second turbine housings (110, 210) in    relation to one another.-   10. Two-stage turbocharger system (10) having    -   a first exhaust gas turbocharger (100) with a first turbine        housing (110), and    -   a second exhaust gas turbocharger (200) with a second turbine        housing (210),    -   wherein, situated in the area of a first flange (120) on the        first turbine housing (110), the first turbine housing (110)        features a pocket (130), into which projects a projection (230),        which is situated in the area of a second flange (220) on the        second turbine housing (210), characterized in that the        projection (230) is designed such that, during the connection of        the first and second turbine housings (110, 210), after the        projection (230) has been inserted into the pocket (130), the        first and second turbine housings (110, 210) can be tilted in        relation to one another in order to establish a flush connection        between the first flange (120) and the second flange (220).-   11. Two-stage turbocharger system according to embodiment 10,    characterized in that the pocket (130) is situated in a wall of the    first turbine housing (110) extending from the first flange (120).-   12. Two-stage turbocharger system according to embodiment 10 or    embodiment 11, characterized in that the projection (230) is    designed in the form of a strip, which extends in a linear direction    from an outer wall (214) of the second turbine housing (210) and    runs approximately parallel to a plane along which lies a connection    area (222) for the second flange (220).-   13. Two-stage turbocharger system according to any of the    embodiments 10 to 12, characterized in that the projection (230) has    a lower side (232), which is disposed opposite a connection area    (122) on the first flange (120) and features a chamfer (234).-   14. Two-stage turbocharger system according to embodiment 13,    characterized in that the chamfer (234) has a chamfer angle of from    2° to 7°, in particular from 4° to 5°.-   15. Two-stage turbocharger system according to any of the    embodiments 10 to 14, characterized in that at least one connection    means (700) is provided in order to attach the second turbine    housing (210) to the first turbine housing (110).-   16. Two-stage turbocharger system according to any of the    embodiments 10 to 15, characterized in that a seal (600) is situated    between the first flange (120) and the second flange (220).-   17. Two-stage turbocharger system according to any of the    embodiments 10 to 16, characterized in that also at least one    locating pin (140) is provided in order to establish the position of    the second turbine housing (210) in relation to the first turbine    housing (110) during assembly.-   18. Two-stage turbocharger system according to embodiment 17,    characterized in that the locating pin (140) is situated in the    connection area (122) of the first flange (120) and interacts with    the projection (230) in order to position the first and second    turbine housings (110, 210) in relation to one another.-   19. Two-stage turbocharger system according to any of the    embodiments 10 to 18, characterized in that the two-stage    turbocharger system (10) furthermore features a first compressor    housing (300) having a compressor inlet (310) and a second    compressor housing (400) having a compressor outlet (410), wherein    the compressor outlet (410) and the compressor inlet (310) are    connectable with one another by way of a plug connection (500).-   20. Two-stage turbocharger system according to embodiment 19,    characterized in that the plug connection (500) is designed to have    a tubular shape and feature a rigid center tube as well as a    flexible outer casing.-   21. Two-stage turbocharger system according to embodiment 20,    characterized in that there is a sealing bead (510) at each end of    the tube-shaped plug connection (500).-   22. Method for assembling a two-stage turbocharger system having a    first exhaust gas turbocharger (100), which features a first turbine    housing (110), and    -   a second exhaust gas turbocharger (200), which features a second        turbine housing (210), comprising:    -   inserting a projection (230) on the second turbine housing (210)        into a pocket (130) in the first turbine housing (110);    -   tilting the first turbine housing (110) and the second turbine        housing (210) in relation to one another such that the first        flange (120) of the first turbine housing (110) is situated        flush against the second flange (220) of the second turbine        housing (210); and    -   attaching the first turbine housing (110) to the second turbine        housing (210).-   23. Method according to embodiment 22, furthermore comprising    connecting a compressor inlet (310) of a first compressor of the    two-stage turbocharger system with a compressor outlet (410) of a    second compressor of the two-stage turbocharger system by way of a    plug connection (500) during the insertion of the projection (230)    into the pocket (130).

1. An apparatus for connecting an exhaust gas outlet (112) of a firstturbine housing (110) with an exhaust gas inlet (212) of a secondturbine housing (210) in a two-stage turbocharger system (10) having apocket (130) situated in the area of a first flange (120) on the firstturbine housing (110), and a projection (230), which is situated in thearea of a second flange (220) on the second turbine housing (210) andcan be inserted into the pocket (130), wherein the projection (230) isdesigned such that, after the projection (230) has been inserted intothe pocket (130), the first and second turbine housings (110, 210) canbe tilted in relation to one another in order to establish a flushconnection between the first flange (120) and the second flange (220).2. The apparatus according to claim 1, wherein the projection (230) isdesigned in the form of a strip, which extends in a linear directionfrom an outer wall (214) of the second turbine housing (210) and runsapproximately parallel to a plane along which lies a connection area(222) for the second flange (220).
 3. The apparatus according to claim1, wherein the projection (230) has a lower side (232), which isdisposed opposite a connection area (122) on the first flange (120) andfeatures a chamfer (234).
 4. The apparatus according to claim 1, whereinat least one connection means (700) is provided in order to attach thesecond turbine housing (210) to the first turbine housing (110).
 5. Theapparatus according to claim 1, wherein furthermore at least onelocating pin (140) is provided in order to establish the position of thesecond turbine housing (210) in relation to the first turbine housing(110) during assembly.
 6. A two-stage turbocharger system (10) having afirst exhaust gas turbocharger (100) with a first turbine housing (110),and a second exhaust gas turbocharger (200) with a second turbinehousing (210), wherein, situated in the area of a first flange (120) onthe first turbine housing (110), the first turbine housing (110)features a pocket (130), into which projects a projection (230), whichis arranged in the area of a second flange (220) on the second turbinehousing (210), wherein, during the connection of the first and secondturbine housings (110, 210), the projection (230) is designed such that,after the projection (230) has been inserted into the pocket (130), thefirst and second turbine housings (110, 210) can be tilted in relationto one another in order to establish a flush connection between thefirst flange (120) and the second flange (220).
 7. The two-stageturbocharger system according to claim 6, wherein the projection (230)is designed in the form of a strip, which extends in a linear directionfrom an outer wall (214) of the second turbine housing (210) and runsapproximately parallel to a plane along which lies a connection area(222) for the second flange (220).
 8. The two-stage turbocharger systemaccording to claim 6, wherein the projection (230) has a lower side(232), which is disposed opposite a connection area (122) on the firstflange (120) and features a chamfer (234).
 9. The two-stage turbochargersystem according to claim 6, wherein at least one connection means (700)is provided in order to attach the second turbine housing (210) to thefirst turbine housing (110).
 10. The two-stage turbocharger systemaccording to claim 6, wherein a seal (600) is situated between the firstflange (120) and the second flange (220).
 11. The two-stage turbochargersystem according to claim 6, wherein furthermore at least one locatingpin (140) is provided in order to establish the position of the secondturbine housing (210) in relation to the first turbine housing (110)during assembly, in particular wherein the locating pin (140) issituated in the connection area (122) of the first flange (120) andinteracts with the projection (230) in order to position the first andsecond turbine housings (110, 210) in relation to one another.
 12. Thetwo-stage turbocharger system according to claim 6, wherein thetwo-stage turbocharger system (10) furthermore features a firstcompressor housing (300) having a compressor inlet (310) and a secondcompressor housing (400) having a compressor outlet (410), wherein thecompressor outlet (410) and the compressor inlet (310) are connectablewith one another by way of a plug connection (500).
 13. The two-stageturbocharger system according to claim 12, wherein the plug connector(500) is designed to have a tubular shape and features a rigid centertube as well as a flexible outer casing, wherein there is a sealing bead(510) at each end of the plug connector (500).
 14. A method forassembling a two-stage turbocharger system (10) having a first exhaustgas turbocharger (100), which features a first turbine housing (110),and a second exhaust gas turbocharger (200), which features a secondturbine housing (210), comprising: inserting a projection (230) on thesecond turbine housing (210) into a pocket (130) in the first turbinehousing (110); tilting the first turbine housing (110) and the secondturbine housing (210) in relation to one another such that the firstflange (120) of the first turbine housing (110) is situated flushagainst the second flange (220) of the second turbine housing (210); andattaching the first turbine housing (110) to the second turbine housing(210).
 15. The method according to claim 14, furthermore comprisingconnecting a compressor inlet (310) of a first compressor of thetwo-stage turbocharger system (10) with a compressor outlet (410) of asecond compressor of the two-stage turbocharger system (10) by way of aplug connection (500) during the insertion of the projection (230) intothe pocket (130).
 16. The apparatus according to claim 1, wherein theprojection (230) has a lower side (232), which is disposed opposite aconnection area (122) on the first flange (120) and features a chamfer(234) with a chamfer angle of from 2° to 7°.
 17. The apparatus accordingto claim 1, wherein the projection (230) has a lower side (232), whichis disposed opposite a connection area (122) on the first flange (120)and features a chamfer (234) with a chamfer angle of from 4° to 5°. 18.The two-stage turbocharger system according to claim 6, wherein theprojection (230) has a lower side (232), which is disposed opposite aconnection area (122) on the first flange (120) and features a chamfer(234), wherein the chamfer (234) has a chamfer angle of from 2° to 7°.19. The two-stage turbocharger system according to claim 6, wherein theprojection (230) has a lower side (232), which is disposed opposite aconnection area (122) on the first flange (120) and features a chamfer(234), wherein the chamfer (234) has a chamfer angle of from 4° to 5°.